Powermatic 3520b Tailstock Swing-Away Problem

[Izzy Charo]

Hello, I think this has been discussed a bit before...I'm having a lot of difficulty (and frustration!) installing the swing-away bed extension. Very difficult to get it lined up precisely with the bed ways... if you're off just a hair either up/down or left/right the tailstock hangs up and won't move onto the extension. There are 3 bolts, and 2 set screws (?jack screws) that attach the extension to the lathe. I confess I'm not sure what the set/jack screws are supposed to do...can anyone shed some light on the correct procedure to attach this extension? At this point I'm thinking that the machining on the extension is off a bit, and I might have to break out the pneumatic grinder...Thanks!

[Wally Crawford]

Set screws are fastening screws. You may be familiar with them on a four jaw chuck to keep it from backing off the spindle in reverse. It is a bit of a stretch, but the grub screw on your banjo might be considered a set screw.

Jack screws are, as the name implies, used to raise or lower component.

The procedure I have always used is to loosen the set screws, use the jack screws to position the ways in alignment, and then tighten the set screws. You may have to do it a couple times for perfect alignment.

I would discourage you from attacking it with a grinder.

[Izzy Charo]

Thanks for the clarification....on mine, there are 2 large bolts, and 2 much smaller "set" screws. are the bolts what you are referring to as jack screws? I am unable to get the extension ways in alignment with the lathe bed with those...I can come close, but not enough for the tailstock to slide over and back smoothly. Appreciate the help!

[Patrick Morris IV]

It may sound counter-intuitive, but you might try turning the tail-stock around and locking it in place over the junction to help with the alignment of the extension.

[Wally Crawford]

A picture would be a huge help. Can you post a pic so that we may be able to help you more?

[mike johnston]

Funny to find this post. As I had logged on just to complain about the same thing for my 3520 c and swing away. Just as you’ve said a real pain to adjust. I ended up calling a friend, who was a friend of the original designer of this swing away. A gentleman named Tom who used to be on sawmill creek occasionally. Anyway the way Tom used to tell people how to align it goes like this. Loosen bolts on swing away a little, slide tail stock onto swing away align the little round disk that acts as a clamp for tail stock half on lathe half on swing away, then tighten. Now retighten the bolts on swing away. To me this version of the swing away is really lacking. With half the tail stock hanging off the swing away. Not at all like the original designed by Tom. I will be revamping mine

[Izzy Charo]

Is the idea that you tighten the bolts when the clamp is halfway on the tailstock/swing-away, and then you can slide the tail-stock completely onto the swing-away? You should be able to slide the tailstock completely onto the swing-away; FYI: I spoke with tech assistance at Powermatic; no help at all. I suspect the swing-away is just not milled correctly...I haven't had time to work on this recently, but will post again if I ever get it working correctly.

[Jim Morgan]

Is the idea that you tighten the bolts when the clamp is halfway on the tailstock/swing-away, and then you can slide the tail-stock completely onto the swing-away? You should be able to slide the tailstock completely onto the swing-away; FYI: I spoke with tech assistance at Powermatic; no help at all. I suspect the swing-away is just not milled correctly...I haven't had time to work on this recently, but will post again if I ever get it working correctly.

Yes: use the tailstock clamp to align the swing-away and the bed. Afterwards, you should be able to fully slide the tailstock onto the swing-away. Once you get it aligned, you'll be glad you have it!

You should be able to do some investigation with a straight edge and feeler gauge to see more precisely what the problem is. Is the swing-away higher than the bed? Lower than the bed? Too far forward relative to the bed? Too far backward? Are the swing-away and bed not coplanar?

As Wally Crawford said several weeks ago, posting pictures might be helpful.

[Izzy Charo]

Apologies for not posting a picture... I have tried to align this so many different ways I wasn't sure which picture to take, or if it would help. So, I'll keep at this, but so far it appears that when I get the swing-away level where it meets the lathe ways, the rear end of the swing-away is too high...hence the tailstock not sliding all the way onto it. I think I need to work more with the set screws to fix this issue. I'll try to grab some pictures and post. Thanks for the help!
(PS: If you're listening Powermatic: It really shouldn't be this hard...this is a poorly designed add-on, in my opinion)